CEE103 - Lecture No 04.pdf applied electricity

lecture

1. CEE103 –Applied Electricity &
Electronics
Course Instructor: Engr. Riaz H. Junejo
Lecture No. 04
Topic: Circuit Elements
Semester: Fall 2020
Department of Electrical & Computer Engineering
CUI Wah Campus.

2. 1.6 Circuit Elements
▪There are two types of elements in electric circuits:
▪Passive element: Passive element cannot generate energy, but it absorbs the energy.
▪Resistors, capacitors, inductors
▪Active element: It is capable of generating energy.
▪Generators, batteries, operational amplifiers
▪The most important active elements are voltage or current sources that deliver
power to the circuit.
▪There are two kinds of sources:
▪Independent sources
▪Dependent sources.

3. Independent Sources
▪An ideal independent source is an active element that provides a specified
voltage or current that is completely independent of other circuit variables.
▪An ideal independent voltage source delivers whatever current is necessary to
maintain its terminal voltage.
▪An ideal independent current source is an active element that provides a
specified current completely independent of the voltage across the source.

4. Dependent Sources
▪An ideal dependent (or controlled) source is an active element in which the
source quantity is controlled by another voltage or current.
▪There are four possible types of dependent sources:
▪A voltage-controlled voltage source (VCVS)
▪A current-controlled voltage source (CCVS)
▪A voltage-controlled current source (VCCS)
▪A current-controlled current source (CCCS)
▪Dependent sources are useful in modeling
elements such as transistors, opampsand ICs.

5. Example
▪Calculate the power supplied or absorbed by each element in the circuit shown.
▪Solution: Since 5A current comes from the +veterminal of the source, we have:
▪??????
1=20−5=−100�
▪For ??????
2and ??????
3, current flows from +veto –ve
terminals of the elements, hence:
▪??????
2=5×12=60�,????????????????????????
2=8×6=48�
▪For ??????
4,the voltage is 8�(+veat the top)
▪Hence, ??????
4=8−0.2??????=8−0.2×5=−8�

6. Electricity Bills
▪The electricity cost depends on the amount of energy consumed in kilowatt-
hours (kWh).
▪1kWh is known as one unit of the electricity.

7. Example:
▪A homeowner consumes 700 kWh energyinJanuary.Determinetheelectricity
billforthemonthusingthefollowingresidential rate schedule:
▪Basemonthlycharge????????????.100
▪First 100 kWh per month at Rs. 8/kWh.
▪Next 200 kWh per month at Rs.11/kWh
▪Over 300 kWh permonthatRs.13/kWh.
▪Solution:Wecancalculate the electricity bill as follows:
▪Basemonthly fix charges = Rs. 100
▪First100kWh@Rs. 8/kwh=Rs.800
▪Next 200 kWh @ Rs. 11/kwh = Rs. 2200
▪Remaining400kWh@Rs. 13 = Rs. 5200
▪Totalbill=7200
▪Averagecost=
8300
100+200+400
=????????????.11.85/??????�ℎ

8. Thank You!